Virulence Factors ofEscherichia coliIsolated From Female Reproductive Tract Infections and Neonatal Sepsis

Abstract

Objective:The presence of enterobacteria such asEscherichia coliin the vagina of normal women is not synonymous with infection. However, vaginalE. colimay also cause symptomatic infections. We examined bacterial virulenceproperties that may promote symptomatic female reproductive tract infections (RTI) and neonatal sepsis.Methods:E. coliisolated as the causative agent from cases of vaginitis (n = 50), tubo-ovarian abscess (n = 45) and neonatal sepsis (n = 45) was examined for selected phenotypic and genetic virulence properties. Results were compared with the frequency of the same properties among fecalE. colinot associated with disease.Results:A significantly greater proportion of infectionE. coliexhibited D-mannose resistant hemagglutination compared with fecalE. coli(p< 0.01). This adherence phenotype was associated with the presence of P fimbriae (pap) genes which were also significantly more prevalent among isolates from all three infection sites (p< 0.01). The majority ofpap+isolates contained thepapG3allele (Class II) regardless of infection type. Increased frequency of Type 1C genes among vaginitis and abscess isolates was also noted. No significant differences in frequency of other bacterial adherence genes, fim, sfa, uca (gaf) or dra were observed. E. coli associated with vaginitis was significantly more likely to be hemolytic ( HIY+) than were fecal isolates (p< 0.05). The HIY+phenotype was also more prevalent among tubo-ovarian abscess and neonatal sepsis isolates (p< 0.08).Conclusions:E. coliisolated from female RTI and neonatal sepses possess unique properties that may enhance their virulence. These properties are similar to those associated with otherE. coliextra-intestinal infections, indicating that strategies such as vaccination or bacterial interference that may be developed against urinary tract infections (UTI) and otherE. coliextra-intestinal infections may also prevent selected female RTI.